Turning and boring tool



Dec. 29, 1931. .1. ARCHER TURNING AND BORING TOOL Filed Nov. 1929 Patented Dec. 29, 1931 UNITE'DISTATEST JOHN ARCHER, or SHEFFIELD, ENGLAND, Assmnoit r0 ENGLISH STEEL commune l LIMITED, or SHEFFIELD, ENGLAND V p v running A111) Bonfire Toot Application filed november n, 1929; Serial n 406,406, and iii Great Britainpecember 5, 1928.

This invention relates to turning, boring and like tools of the type in which a detachable cutter having taper sides is'secured to. a holder by a centralfstud or the like with the cutter side supported by a'shoulder or recess wall on the holder, theobjectofthe invention being, to provide improved means for securing the cutterto the holder.

As usually made the cuttingpoints or edges of the cutter are formed at-the junctionofits taper sides with the larger end surface and when worn anew point or part of the'edge may be brought into'operation by turning the cutter about the central stud or the like. Ac-

;; cording to the presentinvention-which mayv be "applied also to tools used for shaping, planing and other purposes, the sides of the cutter are formed with a waist, the holder is provided with an undercut shoulder or wall fitting the tool waist, and a wedgingepin engages an axial hole in the cutter and a hole in the holder which isslightly nearer than the one in thecutter to the undercut shoulder or wall when the cutter is-in contact-therewith. The action of the wedging p111 tends to draw these holes into register" and thus presses the cutter against the supporting shoulder or wallof the holder.

In the accompanying drawings Figure 1 is an elevation of a'holder carry-s ing a tool at each end according to the present invention, one end of the holderbeing shown in central longitudinal section.

, Figure 2 is a plan of Figure 1.

Figure 3 is a view similar to Figure 2 show-' ing differentlyshaped cutters carried by the holder. 1

Figure 4; is a sectional elevation illustrat ing a modification.

Like reference numerals indicate like parts throughout the drawings.

In carrying out thepresent invention as illustrated the cutter 10 is provided withoutting points or edges 11 at one end and with a base 12' at the other end, the sides between the two ends 11 and 12 being tapered inwardly from both ends to form a waist 13. The holder 14 is of bar form and is recessed at one or both ends toprovide a shoulder or'wall 15 i which is undercut'at 16 to fit the'waist '13 of? the cutter'll as shown, for example, on theleft-hand side of Figure 1. I The base 12 of the cutter 10 rests on the recessed end of the holder l t-and its waist 13 or'dove-tail like part of the side below that waist is pressed against the undercut portion 16 of the shoulder or wall15 by wedge action; s V

In the construction illustrated this wedge action. is-setup by a pin having a cylindrical portion 17 sliding in a central cylindrical hole through the cutter 10 and a tapered portion 18 engaging a similarly'tapered hole in the recessed part of the holder 14. The required wedge action is ensured by the disposition of the central hole in the cutter 10 in relation to the one of the holder :14, the lat-t ter. hole being slightly nearer than the former to the undercutshou'lder or wall 15, 16 when.

holes into register and thus presses the cutter.

against the supporting shoulder 15, 16. The parts are preferably arranged for this pressure to beexerted against the undercut portion16= of the shoulder 15, with a clearance, asillustrated, between the remainder of, the shoulder and the side of the toolbetween the waist 13 and cutting edge or points 11. If desired, however, the shoulder or wall 15 may be arranged to be in contact with the tool or both sides of its waist 13'. V

It will be appreciated that, as thehole in the holder and the part 18 of the pin engaging it are bothbf-a similar tapered formation. as illustrated, the sides of both being inclined to theaxis at the same angle, at the beginning of thewedging action the relative dis position of the holes in the cutter 10 and in holder 14:. This construction gives a substantial bearing surface between the pin and both the holder and the cutter, but in modified 10 the hole-in the cutter adjacent to the shoulder 15, 16 being normal to its base and the opposite side of the hole in the holder being inclined to correspond with the angle of the wedge or vice versa.

The undercut shoulder 15, 16 is preferably straight and inclined to the length of the holder 14 as shown in Figures 1, 2 and 3 and it will be appreciated that any shape of cutter may be secured to the holder by making each of them with its waist 13 at the same distance from its central hole, this distance being measured on the line 19 (Figures 2 and 3) normal tothe waist passing through the I centre of the hole. A square cutter is thus shown secured at the left-hand end of the holder in Figures 1 and 2, a triangular form at the corresponding end of the holder in Figure 3 whilst a pentagonal shape is shown at the right-hand end of Figure 3. A circular cutter is shown at the right-hand side of Figures 1 and 2 and in order to enable it to be interchangeable with the other shapes of cutter and to provide increased bearing surface on the undercut shoulder 15,

16, its tapered sides betweenits base 12 and waist 13 are made flat as shown at 20. In Figures 1 and 2 these flat sides 20 of the cutter engaging the undercut shoulder 15, 16 are shown hexagonal in outline. al-

0 though they may beof other shape if desired.

Similarly in all cases the outline of the parts of the cutter engaging the undercut shoulder 15, 16 may. if desired, differ from the outline of the cutting edge 11 and the shoulder or wall 15 be shaped to correspond with the portion of the outline engaged thereby, the outline of the cutting edge being of any desired shape.

When the cutter 10 is to beused withits cutting edge or points 11 uppermost the wedging pin 17, 18'is preferably inserted through the cutter into the holder as shown in Figure 1, the pin tapering from its cylindrical portion 17 to a smaller diameter. Although the tool so secured may be used with the cutting points or edges facing downwards there may then be some risk of the pin falling out and to avoid this it may be inserted through the hole in 6Q the holder intothe one in the cutter, asillustrated in Figure 4. In thiscase the tapered portion 18 of the pin is oppositely arranged, the wedging pin tapering to a smaller. diameter towards thecylindrical portion 17.

it! The wed'ging and locking act-ion is, however,

the same as that previously described with reference to F i re 1.

In both the constructions illustrated in Figure 1 and in Figure 4 the taper 18 of the Wedging pin is of the same inclination as that of the hole in the holder engaged thereby, but these tapers are so formed as to provide a clearance 21 between them in the locking position on the side adjacent to the undercut shoulder 15, 16 of the holder. The provision of this clearance 21 ensures the eflicient production of the desired wedging action on the cutter, since in the absence of such a clearance the wedging action would. be limited when the tapered portion 18 reached the end of its longitudinal travel by arriving at a fitting position in the taperedhole therein. The cylindrical portion 17 of the pin is preferably formed accurately to fit the hole in the cutter 10.

As the cutter is sharpened by grinding its operative end face its axial length is gradually decreased and in order that it may remain eiiicient when the cutting points or edges 11 are ground to proximity with the waist 13 the angles between the inwardly tapered sides below the waist, immediately under the cutting points 11, are preferably removed by grinding or otherwise as indicated at 22 in order to providethe necessary clearance between the base of the cutter and the work. For a like reason the undercut-wall 15, 16 of the holder is preferably limited in height to be less than the axial length of the cutter 10 as illustrated, and the waist 13 is preferably nearer to the base 12 than to the cutting points 13 in the base of a new cutter, being asnear to the base as is consistent with an adequate engagement by the undercut portion 16 of the wall 15.

VJ hat I claim is 1. In a metal cutting tool the combination of a cutter having its sidesconverging from both ends to form a waist intermediate the ends, a holder having an. undercut shoulder fitting the cutter waist and disposed to take both the thrust of the tool feed and the tilt of the tool due to cutting pressure and a Wedging pin engaging an axial hole in the cutter and a hole in the holder which is slightly nearer than the one in the cutter to the undercut shoulder when the cutter is in contacttherewith, substantially as and for the purpose specified.

2. In a metal cutting tool the combination of a cutter having its sides converging from both ends to form a waist intermediate the ends, a holder having an undercut shoulder fitting the cutter waist and disposed to take both the thrust of the tool feed and the tilt of the tool due to cutting pressure and a wedging pin having a cylindrical port-ion sliding in a cylindricalholeinthe cutter and a tapered portionengaging a, tapered hole in the holder, substantially as specified.

3. In a metal cutting tool the combination of a cutter having its sides converging from both ends to form a waist intermediate the ends, a holder having an undercut-shoulder fitting the cutter waist and disposed to take both the thrust of the tool feed and the tilt of the tool due to cutting pressure, and a wedging pin having a cylindrical portion sliding in a cylindricalhole in the cutter and a tapered portion engaging a'tapered hole in the holder to lock the cutter waist in engagement with the shoulder, the tapers of the wedging pin and of the hole in the holder being formed to provide a clearance between them in the locking position on the side adjacent to the shoulder, substantially as specified.

4. In a metal cutting tool the combination of a cutter having a circular operative edge at one end and flat sides inwardly tapered from a flat base of polygonal outline to form a waist, a holder having an undercut shoulder fitting the cutter waist and disposed to take both the thrust of the tool feed and the tilt of the tool due to cutting pressure and a wedging pin engaging an axial hole in the cutter and a hole in the holder which is slightly nearer than the one in the cutter to the undercut shoulder When the cutter is is contact therewith, substantially as and for the purpose specified.

5. In a metal cutting tool the combination of a cutter having a flat base of polygonal outline and sides inwardly tapered from the base to form a waist with the corners between the tapered sides removed between the waist and base, a holder having an undercut shoulder fitting the cutter waist and disposed to take both the thrust of the tool feed and the tilt of the tool due'to cutting pressure and a wedging pin engaging an axial hole in the cutter and a hole in the holder which is.

slightly nearer than the one in the cutter to the undercut shoulder when the cutter is in contact therewith, substantially as .and for the purpose specified.

6. In a metal cutting tool the combination of a cutter having an operative edge at one end and its sides tapered inwardly to form a waist nearer to its base than to its operative edge, a holder having an undercut shoulder fitting the cutter waist and disposed to take both the thrust of the tool feed and the tilt of the tool due to cutting pressure of less height than the axial length of the cutter, and a wedging pin engaging an axial hole in the cutter and a hole in the holder which is slightly nearer than the one in the cutter to the undercut shoulder when the cutter is in contact therewith, substantially as and for the purpose specified.

7 In a metal cutting tool the combination t1on engagin 'tion engaging a tapered hole in the holder to lock the cutter waist in engagement with the shoulder, the tapers of the wedging pin and of the'hole in the holder being formed to provide a clearance between them in the looking position on the side adjacent to the v shoulder, substantially as specified.

8. In a metal cutting tool the combination 7 ofa cutter having its sides converging from both ends to form a waist intermediate the ends, a holder having an undercut shoulder fitting the cutter waistand disposed to take both the thrust of the tool feed and the tilt of the tool due to cutting pressure and a wedgeing pin having a cylindrical portion sliding in a cylindrical hole in, the cutter and a tapered portion engaging a tapered hole in the holder which is slightly nearer than the one in the cutter to theundercut shoulder when the cutter is in contact therewith in a locking position, the tapers of the wedging pin and of the hole in the holder being formed to rovide a clearance between them in the loc ing position on the side adjacent to the shoulder, substantially as specified.

.9. In a metal cutting tool the combination of a cutter having an operative edge, a fiat base of polygonal outline and sides inwardly tapered from the base to form a waist nearer to its base than to its. operative edge with the corners between the tapered sides removed between the waist and base, a holder having an undercut shoulder fitting the cutter waist and disposed to take both the thrust of the tool feed and the tilt of the tool due to cutting pressure of less height than the axial length of the cutter, and a wedging pin having a cylindrical portion sliding in a cylindrical hole in the cutter anda tapered pora tapered hole in the holder which is slig tly nearer than the one in the cutter to the undercut shoulder when the cutter is in contact therewith in a locking position, the tapers of the wedging pin and of the hole in the holder being formed to provide a clearance between them in the locking position on the side adjacent to the shoulder, substantially as specified. 7

In testimony whereof I hereunto afiix my signature.

J ARCHER.

of a cutter having a circular operative edge 

